强酸性阳离子交换树脂对铅的吸附行为及机理

通过静态吸附实验,研究了Pb2 在001×7强酸性阳离子交换树脂上的吸附行为,并从热力学和动力学方面对吸附过程进行了分析,用红外光谱的方法探讨了001×7树脂吸附Pb2 的机理.结果表明在所研究的浓度范围内,Pb2 在001×7树脂上的吸附平衡数据符合Freundlich等温吸附方程,吸附为自发进行的放热过程;液膜扩散为Pb2 在001×7树脂上吸附速率的主要控制步骤,随着振荡频率的增加,吸附速率会逐渐增大;最佳的吸附pH在4左右,用3 mol/L的硝酸对饱和树脂进行洗脱再生,洗脱率可达98%以上;298 K温度下树脂的静态饱和吸附容量为414 mg/g(湿树脂).     

强碱性离子交换纤维吸附Cr(Ⅵ)的热力学(英文)

通过静态吸附实验,采用强碱性离子交换纤维(SAAEF)去除水溶液中的Cr(VI)。分别研究了时间、Cr(Ⅵ)的初始浓度和pH对该吸附过程的影响。SAAEF的最大饱和吸附量为187.7mg/g(pH=1)。饱和吸附量随着Cr(VI)浓度的升高而增大,在pH1的酸度范围内,随着pH值的增高而减少。采用Langmuir、Freundlich、Dubinin-Radushkevich和Temkin4种热力学模型对不同温度的等温吸附曲线进行拟合,结果表明,Langmuir等温吸附模型是描述SAAEF吸附Cr(VI)热力学过程的最佳模型;模型参数表明,SAAEF吸附Cr(VI)的过程既存在物理吸附又存在化学吸附。热力学参数ΔH、ΔG和ΔS表明,该吸附过程为一放热、熵增的自发过程。热力学参数Q(iso)不为常量,表明SAAEF表面存在能量分布不均匀的现象。     

201×7阴离子交换树脂对低浓度铂的吸附性能

研究了用201×7强碱性阴离子交换树脂对氯化浸出液中低浓度铂的吸附性能,考察了树脂用量、吸附时间、pH值、反应温度等因素对树脂吸附铂的影响。实验结果表明,pH=1.0时树脂的吸附效果最佳,静态饱和吸附容量可达到190 mg Pt/g干树脂,铂在201×7树脂上的吸附是吸热反应,温度升高有利于铂的吸附,吸附反应热焓变ΔH=36.72 kJ/mol,熵变为ΔS=0.190 kJ/(mol·K)。对201×7树脂吸附铂的吸附等温模型及动力学进行了分析,结果表明,吸附平衡过程符合Langmuir等温式,且为优惠吸附;铂的吸附过程符合准二级动力学方程,准二级常数为k2=1.58×10-4g/(mg·min)。用2.4 mol/L的高氯酸可将载铂树脂中的铂洗脱,洗脱率为83%。     

盐酸介质中Mannich碱缓蚀剂在碳钢表面的吸附热力学研究

合成了四种Mannich碱，利用Bockris置换模型与统计模型，计算得出盐酸介质中其在A3钢表面的吸是一个以化学吸附为主，放热、熵减、可以自动发生的过程。两模型计算所得到的热力学函数不同的原因在于研究的反应不同。     

001×14.5强酸性树脂对铬(Ⅲ)的吸附性能

采用离子交换树脂法吸附铬(Ⅲ),通过树脂选型确定强酸性阳离子交换树脂001×14.5对铬(Ⅲ)吸附容量最大,用所选的001×14.5树脂研究铬(Ⅲ)的吸附性能。静态吸附实验表明:转速大于120 r/min时,对树脂吸附的影响可忽略,即外扩散基本消除,pH=7.0时,吸附最佳,铬(Ⅲ)吸附率随树脂用量的增加而增大;001×14.5树脂吸附铬(Ⅲ)的过程符合Langmuir等温曲线,且为优惠吸附;吸附过程符合拟二级动力学方程,吸附过程的表观活化能Ea=23.4 kJ/mol,颗粒内扩散为吸附速率的主要控制步骤;用1 mol/L的硫酸对吸附后的饱和树脂进行脱附再生,脱附率可达99%。     

交换性离子和pH值对酸性土壤腐蚀的影响

研究了交换性酸度总量、交换性H+、交换性铝对A3钢在酸性土壤中的腐蚀影响.结果 表明：深圳土作为酸性土，它的缓冲性能很强，加不同pH的硝酸，对其pH值影响不大； 随硝酸的pH的增加，交换性铝、交换性酸度总量、交换性H+有相对减小的趋势，腐蚀速 率增大.当土壤pH约为4时，阴极过程发生变化，由氧放电转为氢放电.     

离子交换法除去高纯铂中杂质离子的研究

通过理论分析选择具有合适功能基的离子交换树脂用于高纯铂的制备,并对离子交换过程中铂溶液的浓度、pH值对贵、贱金属杂质去除效果的影响进行了研究。研究表明:001×7型强酸性阳离子树脂可以满足酸性条件下对阳离子杂质元素的选择性吸附;当铂浓度为50 g/L,在pH=1.5时K、Ca、Si、Pb等贱金属杂质得到去除,在pH=3时Au、Ag、Ir、Pd等贵金属杂质除去效果良好。提纯后的氯铂酸经化学沉淀、煅烧得到了纯度为99.999%的高纯铂。     

改性玉米芯吸附溶液中U(Ⅵ)的热力学特征

以微波辅助KMnO4改性玉米芯为吸附剂来吸附溶液中的U(Ⅵ),探讨改性玉米芯吸附溶液中U(Ⅵ)的热力学特征。结果表明:随着温度的升高,改性玉米芯对U(Ⅵ)的吸附量增大。Langmuir模型能更好地反映吸附过程特征,说明吸附主要发生在改性玉米芯表面的活性区域,属于单分子层吸附。吸附热力学参数ΔG、ΔH和ΔS的计算结果表明,所有温度下ΔG在U(Ⅵ)初始浓度≤80 mg/L时均为负值,且温度越高ΔG值越负,表明改性玉米芯对U(Ⅵ)的吸附过程是一个自发的过程,且温度越高,自发程度越大。焓变ΔH和熵变ΔS都为正值,说明吸附过程吸热,温度越高,越有利于吸附的进行。     

表面氨基化细菌纤维素对水中重金属离子吸附的热力学与动力学(英文)

以细菌纤维素(BC)为原料,通过化学改性法制备新型、高效且价廉的吸附材料——表面氨基化细菌纤维素,并对其进行表征及分析;同时以Cu~(2+)、Pb~(2+)和Cd~(2+)为研究对象,对其吸附热力学和动力学特性进行研究,并探讨吸附机理,建立数学模型。结果表明:氨基化细菌纤维素对Cu~(2+)、Pb~(2+)和Cd~(2+)的吸附过程更好地符合Langmuir等温方程和准二级反应动力学模型,说明吸附过程为单分子层吸附,以化学吸附作用为主。Elovich方程、粒子内扩散模型也能很好地反映吸附模式,说明是其吸附液膜扩散和粒子内扩散共同作用的结果。吸附过程是吸热反应,适当升高反应温度将有利于吸附发生。     

Adsorption behavior and mechanism of cadmium on strong-acid cation exchange resin

The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.     

季铵型阳离子捕收剂在一水硬铝石和高岭石表面的吸附机理

研究十二烷基三甲基氯化铵（DTAC）和十六烷基三甲基氯化铵（CTAC）对一水硬铝石和高岭石的浮选行为。通过残余浓度法测定吸附等温线,荧光探针法和Zeta电位测试方法研究季铵型阳离子捕收剂在矿物表面的吸附机理。浮选结果表明：将DTAC和CTAC作为捕收剂,一水硬铝石的浮选回收率随着pH的增大而增加,而高岭石的浮选回收率随着pH的增大反而下降。当捕收剂的碳链增长时,矿物浮选回收率提高,但高岭石的增加幅度小于一水硬铝石的。在低浓度范围内,阳离子表面活性剂通过静电作用吸附在一水硬铝石表面,而对于高岭石,还存在离子交换作用。当浓度增大时,阳离子表面活性剂通过碳链间疏水缔合作用在两种矿物表面进一步吸附。矿物表面微极性研究表明：CTAC的疏水性比DTAC强,相同溶液浓度下CTAC在一水硬铝石表面能形成比在高岭石表面更大的胶团,这也说明阳离子表面活性剂碳链的增长对一水硬铝石吸附的影响要大,与浮选结果相吻合。     

Direct extraction of Mo(VI) from acidic leach solution of molybdenite ore by ion exchange resin: Batch and column adsorption studies

The adsorption behavior of ion exchange resin D301 in the extraction of hexavalent molybdenum from high acidic leach solution was investigated. SEM, EDS and Raman spectra analyses were applied to studying the adsorption capacity, reaction kinetics and possible adsorption mechanism in detail. Results showed that the adsorption capacity of D301 resin for molybdenum from high acidic leach solution was up to 463.63 mg/g. Results of the kinetic analysis indicated that the adsorption process was controlled by the particle diffusion with the activation energy 25.47 kJ/mol (0.9α1.2 mm) and 20.38 kJ/mol (0.6α0.9 mm). Furthermore, the molybdenum loaded on the resin could be eluted by using 2 mol/L ammonia hydroxide solution. Besides, dynamic continuous column experiments verified direct extraction of molybdenum from acidic leach solutions by ion exchange resin D301 and the upstream flow improved dynamic continuous absorption.     

Nonlinear dynamics of potassium iodide adsorption on the interface of carbon steel in acidic medium

The development of inhibitors for hydrochloric acidic media is very common. Potassium iodide, in combination with some organic inhibitors, may transform a mediocre inhibitor into an excellent corrosion inhibitor based on a synergetic effect. There is a need to study what happens at the interface in the presence of this compound. The dynamics of the metal electrolyte interface when KI concentration increases has been characterized. The present study has been carried out based on electrochemical impedance spectroscopy and electrochemical noise analysis in the light of nonlinear phenomena by applying recurrence plots and fractal geometry. The fractal dimension of the current–time series shows a direct relationship with the fractal dimension of the surface of steel. The phenomenon of self-organization has been observed on the metal surface. The nonlinear analysis carried out by means of recurrence plots showed that the iodide ions' inhibitory effect is not only simple adsorption but also a nonlinear phenomenon that auto-organizes. The degree of complexity increases, consequently causing an interaction between the microcells and resulting in a lower charge-transfer rate.     

Corrosion inhibition effect and adsorption of aniline derivatives on QD36 steel surface in acidic solution

Inhibition of QD36 steel corrosion in 0.5 M HCl solution by aniline derivatives was studied using chemical (weight loss), potentiodynamic polarization and electrochemical frequency modulation measurements. The adsorption process of studied aniline derivatives on steel surface obeys the Langmuir adsorption isotherm. The values of activation energy (E*_a), adsorption equilibrium constant (K _ads), free energy of adsorption (ΔG _ads ^° , adsorption enthalpy (ΔH _ads ^° ) and adsorption entropy (ΔS _ads ^° )were calculated and discussed. Potentiodynamic polarization measurements showed that aniline derivatives are mixed-type inhibitors. The results obtained by EFM technique were shown to be in agreement with other chemical and electrochemical techniques. Scaning electron microscope (SEM) was used to study the surface morphology of the QD36 steel in 0.5 M HCl solution in the absence and presence of inhibitors. Further, theoretical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.     

Adsorption and inhibition effect of novel cationic surfactant for pipelines carbon steel in acidic solution

A new cationic surfactant was prepared and examined as an inhibitor for the corrosion of carbon steel in 1.0 M HCl solution using weight loss measurements, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The chemical structure of the prepared cationic surfactants has been proven by FTIR spectra. The inhibiting effect of the cationic surfactant as a result of the formation of the protective layer adsorbed on the carbon steel surface The adsorption of the inhibitor was discussed accordingly to the Langmuir isotherm. Polarization data indicated that the cationic surfactant is a mixed-type inhibitor.. The effect of temperature on the corrosion rate of carbon steel in1. 0 M HCl solution devoid of and containing the novel cationic surfactant was examined and thermodynamic parameters were computed. Some surface parameters were calculated and explained.     

The adsorption and corrosion inhibition of some cationic gemini surfactants on carbon steel surface in hydrochloric acid

The adsorption and corrosion inhibition of the gemini surfactants 1,2-ethane bis(dimethyl alkyl (C_nH_2n+1) ammonium bromide) (designated as n−2−n, n=10, 12 and 16) on the steel surface in 1 M hydrochloride acid were studied using the weight loss method. It was found that the adsorption of the gemini surfactants on the steel surface is the main reason to cause the steel corrosion inhibition in hydrochloride acid, and the inhibition efficiency increases with the increase of surfactant concentration and reaches the maximum value near the CMC. A possible adsorption model of gemini surfactant onto the metal surface was also discussed.     

Substitutional adsorption isotherms and corrosion inhibitive properties of some oxadiazol-triazole derivative in acidic solution

A newly synthesized oxadiazol-triazole derivative (TOMP), was investigated as corrosion inhibitor of mild steel in 0.5 M H₂SO₄ solution using weight loss measurements, polarization and electrochemical impedance spectroscopy (EIS) methods. Results obtained revealed that TOMP is effective corrosion inhibitor for mild steel in sulphuric acid and its efficiency attains more than 97.6% at 298 K. The number of water molecules (X) replaced by a molecule of organic adsorbate was determined from the substitutional adsorption isotherms applied to the data obtained from the weight loss experiments performed on mild steel specimen in acidic solution in the 298-333 K range.     

Synthesis of indium oxide nanorods on indium phosphide substrate using plasma immersion ion implantation

We report the preparation of indium oxide (In₂O₃) nanorods on indium phosphide (InP) substrate by plasma immersion ion implantation (PIII). The InP substrate was first treated with PIII of acetylene (C₂H₂) ions, then followed by coating the surface with a 40 nm thick gold film. After rapid thermal anneal (RTA) at 750 °C for 15 s, In₂O₃ nanorods were found on InP surface. The In₂O₃ nanorods with diameters of 50-200 nm were examined by Raman spectroscopy, scanning electron microscopy (SEM) and cathodoluminescence (CL). Nanoparticles of gold were found at the tip of the nanorods, suggesting that a vapour-liquid-solid (VLS) mechanism was involved. However, the fact that other species such as nitrogen, argon or oxygen would not lead to the formation of In₂O₃ nanorods also suggests that the carbon liberated from C₂H₂ plays an important role as a catalyst. Carbon has previously been reported to be a reduction agent for the formation of group III sub-oxides. Such sub-oxides provide the vapour source for the growth of nano-materials through further oxidation.     

The chain length influence of cationic surfactant and role of nonionic co-surfactants on controlling the corrosion rate of steel in acidic media

The corrosion inhibition effect of cationic surfactants, DTAB (Dodecyl Trimethyl Ammonium Bromide) and TTAB (Tetradecyl Trimethyl Ammonium Bromide), on low carbon steel was studied using weight loss, open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements. The effect of chain length compatibility on corrosion inhabitancy of surfactant and co-surfactant was investigated by C₇OH (1-heptanol), C₁₂OH (1-dodecanol) and C₁₅OH (1-pentadecanol) as nonionic co-surfactants in acidic media at different concentrations of DTAB and TTAB. Data represented that the corrosion rate decreased by increasing concentration of DTAB and TTAB, independently. The effect of chain length compatibility on surfactant behavior was discussed. Decreasing of corrosion rate for DTAB + C₁₂OH was more pronounced than other mixtures.